1. Field of the Invention
The present invention relates to improvements in internal combustion engines and, more particularly, to improvements to internal combustion engines of the rotary vee type. Even more particularly, the invention relates to providing a fuel air charge to a power piston by using a supply piston; and an improved bearing for supporting the cylinder block.
2. Description of the Prior Art
Historically, internal combustion engines have been of the four stroke reciprocating designs, wherein a piston or pistons within a stationary block reciprocate (travel back and forth) to provide intake, compression, expansion, and exhaust. The pistons are connected to a crankshaft with piston rods, and the crankshaft delivers the power from the engine. During the intake stroke a valve(s) allows a fresh fuel air charge into the cylinder. During the exhaust stroke another valve(s) opens to allow the burnt fuel air mix to be expelled. These valves are operated by one or more camshafts driven by the crankshaft, however, the means to operate the camshafts that drive the valves can be complex and can increase friction within the engine.
Another type of reciprocating engine is the two-stroke engine. The operating cycle of a two-stroke engine includes a compression stroke and an expansion or power stroke. Exhaust and intake functions occur respectively as the piston approaches and moves away from the bottom dead center position, when the piston uncovers the intake and exhaust ports. Intake occurs in overlapping relation to exhaust, creating incomplete scavenging of the exhaust gases within the cylinder. Because the intake and exhaust ports are in close proximity to each other, and open simultaneously, a portion of the fresh fuel air charge can be lost to the exhaust when both the intake and exhaust ports are opened by the piston, decreasing the efficiency of the engine.
While either the four or two stroke reciprocating engine provides the majority of power for modern cars, light planes, boats, busses, trucks, etc., the reciprocating engine has an inherent problem that vitally effects it's efficiency. In particular, the reciprocation of the piston involves a sequence of acceleration of each piston from rest, followed by a deceleration of each piston to rest. The work done on the pistons during this acceleration and deceleration is not recovered, so the energy necessary to do this work causes a general loss of efficiency of the engine.
A class of engines called the rotary vee holds promise for overcoming the losses due to the reciprocating motion of the conventional internal combustion engine. The rotary vee engine includes two cylinder blocks that are cylindrical in shape and mounted within a housing to allow each cylinder block to rotate. The cylinder blocks contain a plurality of parallel bores, open at one end, to allow insertion of a portion of a double ended piston. The cylinder blocks are angled, relative to each other, between 90 and 180 degrees. The pistons are also angled at the same degree as the cylinder blocks, so as the cylinder blocks rotate within the housing, the pistons rotate with them. As the pistons move from the inside portion of the "V" to the outside portion, the free volumes of the cylinders change, causing compression and expansion.
While the rotary vee holds promise of very smooth and fuel efficient operation, some problems with the prior an engines have kept it from becoming a commercial success. These problems include a fuel air intake system that must operate effectively in the high centrifugal force field of the rotary vee; a cylinder block support system to maintain the vee configuration of the engine while in operation; a cooling airflow system that provides increased engine cooling during high load, low R.P.M. operation; and the ability to control the spark timing for easier starting and better high R.P.M. operation.
In the prior art, the intake and exhaust of a fuel air admix is accomplished as in a two-stroke engine. When the piston approaches bottom dead center, the exhaust port is uncovered first, and then the piston uncovers the intake port. In the high centrifugal force field of the rotating cylinder block of the rotary vee, the fresh fuel air admixture surges through both the intake and exhaust ports when they are uncovered, leaving little or nothing to burn in the next stroke.
One attempt to overcome this problem is disclosed in U.S. Pat. No. 3,905,338 issued Sep. 16, 1975 to William F. Turner, entitled "Vee Engine with Centrifugally Assisted Scavenging." This patent shows intake and exhaust ports machined into the plates that are stacked to form a cylinder block. The design of the ports provides a fresh fuel air admixture in from the radial exterior side of the cylinder, and ports the exhaust inward to the center of the cylinder block and, after the exhaust changes direction 180 degrees, the exhaust is expelled to the outside. The principle is to use centrifugal force to help with the intake and exhaust. Centrifugal force has a greater effect on the heavier cooler fuel air admixture that comes into the cylinder forcing the hot, light exhaust gases to the inside of the cylinder block.
U.S. Pat. No. 4,867,107, issued Sep. 19, 1989 to Robert W. Sullivan, et al. addresses the intake/exhaust porting in essentially the same way as the Turner engine. That is, intake of a fuel air charge occurs from the radial exterior side of the cylinder and the exhaust of the fuel air mix occurs inward to the center of the cylinder block. After changing direction 180 degrees, the exhaust is expelled to the outside. However, unlike the Turner engine where machined plates are stacked to form the cylinder blocks, Sullivan uses an aluminum casting process. Whether the cylinder blocks are cast or machined, the passages that form the intake and exhaust ports adds complexity, and consequently cost, to the cylinder blocks. Another characteristic of the Sullivan engine involves the shape of the outer ends of the pistons, which are machined to provide valving action through the use of the pistons' cyclical and linear motion relative to the cylinder wall, and thus relative to the intake and exhaust ports. The shape of the piston may help with the valving action, however, this shape is not optimum for taking advantage of an expanding gas within a cylinder. To extract the most energy from a fuel air mix, the shape of the piston should be flat or slightly hemispherical.
In the above cited prior art, the classic two stroke problem still remains. That is, the intake and exhaust ports are in close proximity to each other, and open simultaneously, when the piston is at bottom dead center. Thus, the fresh fuel air charge surges through, incompletely scavenging the cylinder and sending a portion of fresh fuel air admixture into the exhaust stream.
Another attempt to overcome the intake/exhaust problems inherent in the rotary vee is shown in U.S. Pat. No. 5,159,902 issued Nov. 3, 1992 to Louis C. Grimm, entitled "Rotary Vee Engine with Through-Piston Induction." This patent proposes the use of hollow pistons and numerous cylinder sleeves. Each sleeve is machined with elongated grooves that align at different degrees of rotation to allow for the intake and exhaust of a fuel air admixture. The sleeves that make up the cylinder walls slide within each other, so the ability to lubricate and keep the sleeves cool while working in the heat and pressure of a cylinder adds an element of complexity and is not a well-proven principle in engine manufacture.
As delineated in Sullivan, described above, because of the angled disposition of the rotating cylinder blocks, combined with the firing of each cylinder at one side of the cylinder block, forces caused by the firing tend to spread the two cylinder blocks into a straight line, that is, out of the vee configuration. Such forces result in drag between the pistons and cylinder blocks that interfere with the operation and efficiency of the engine. Because of this problem, rotary vee engines have not enjoyed much success, despite the promise they hold and, indeed, it has been found that an engine constructed in the rotary vee configuration will often not even operate because of these problems.
Sullivan further describes a solution by which an angled support shaft, running lengthwise through the center of the cylinder blocks and having portions that extend from the ends of the cylinder blocks, is supported by the outer housing in which the cylinder blocks are disposed. While the support shaft can be supported at each end of the housing, support at the apex of the vee is impossible due to the rotation of the cylinder blocks and the pistons.
Sullivan and Turner, described above, show an engine air cooling design, by which the cooling air is drawn in from each end of the cylinder block, over the cylinders for cooling and expelled out the outer housing. Cooling airflow in this configuration is restricted by the fact that the air must flow between the outer housing and the center support shaft. In this configuration, airflow available during high output low RPM operation would appear to be inadequate.
These patents also show that the ignition of the fuel air admixture takes place when a spark plug, while rotating within its respective cylinder block assembly, comes into conduction with a fixed contact. Thus, it is not possible to retard the spark timing for easier starting, or advance the spark timing for fuel efficient high speed, high load operation.